#include <errno.h>

#include <math.h>

#include "proj.h"

#include "proj_internal.h"

PROJ_HEAD(goode, "Goode Homolosine") "\n\tPCyl, Sph";

#define Y_COR 0.05280

#define PHI_LIM 0.71093078197902358062

C_NAMESPACE PJ *pj_sinu(PJ *), *pj_moll(PJ *);

namespace { // anonymous namespace

struct pj_goode_data {

    PJ *sinu;

    PJ *moll;

};

} // anonymous namespace

static PJ_XY goode_s_forward(PJ_LP lp, PJ *P) { /* Spheroidal, forward */

    PJ_XY xy;

    struct pj_goode_data *Q = static_cast<struct pj_goode_data *>(P->opaque);

    if (fabs(lp.phi) <= PHI_LIM)

        xy = Q->sinu->fwd(lp, Q->sinu);

    else {

        xy = Q->moll->fwd(lp, Q->moll);

        xy.y -= lp.phi >= 0.0 ? Y_COR : -Y_COR;

    }

    return xy;

}

static PJ_LP goode_s_inverse(PJ_XY xy, PJ *P) { /* Spheroidal, inverse */

    PJ_LP lp;

    struct pj_goode_data *Q = static_cast<struct pj_goode_data *>(P->opaque);

    if (fabs(xy.y) <= PHI_LIM)

        lp = Q->sinu->inv(xy, Q->sinu);

    else {

        xy.y += xy.y >= 0.0 ? Y_COR : -Y_COR;

        lp = Q->moll->inv(xy, Q->moll);

    }

    return lp;

}

static PJ *goode_destructor(PJ *P, int errlev) { /* Destructor */

    if (nullptr == P)

        return nullptr;

    if (nullptr == P->opaque)

        return pj_default_destructor(P, errlev);

    proj_destroy(static_cast<struct pj_goode_data *>(P->opaque)->sinu);

    proj_destroy(static_cast<struct pj_goode_data *>(P->opaque)->moll);

    return pj_default_destructor(P, errlev);

}

PJ *PJ_PROJECTION(goode) {

    struct pj_goode_data *Q = static_cast<struct pj_goode_data *>(

        calloc(1, sizeof(struct pj_goode_data)));

    if (nullptr == Q)

        return pj_default_destructor(P, PROJ_ERR_OTHER /*ENOMEM*/);

    P->opaque = Q;

    P->destructor = goode_destructor;

    P->es = 0.;

    Q->sinu = pj_sinu(nullptr);

    Q->moll = pj_moll(nullptr);

    if (Q->sinu == nullptr || Q->moll == nullptr)

        return goode_destructor(P, PROJ_ERR_OTHER /*ENOMEM*/);

    Q->sinu->es = 0.;

    Q->sinu->ctx = P->ctx;

    Q->moll->ctx = P->ctx;

    Q->sinu = pj_sinu(Q->sinu);

    Q->moll = pj_moll(Q->moll);

    if (Q->sinu == nullptr || Q->moll == nullptr)

        return goode_destructor(P, PROJ_ERR_OTHER /*ENOMEM*/);

    P->fwd = goode_s_forward;

    P->inv = goode_s_inverse;

    return P;

}

#undef Y_COR

#undef PHI_LIM